Tension device



W. H. SMITH TENSION DEVICE Sept. 17, 1935.

Filed March l5, 1954 ATTORNEY Patented Sept. 17, 1935 UNITED STATES ATENT OFFICE 2 Claims.

The invention relates to a tension device or tensional arrangement for keeping taut a driving band or belt which is movable laterally upon a cylinder or from one pulley to another as from a live driving pulley around which the band is passed onto an adjacent auxiliary or dead pulley.

More specifically the invention relates to a tension device or tensional arrangement for keeping y taut the band in a twister where the band, passed around a live'driving pulley and the whorl of a spindle driven by the pulley, is moved laterally by a stop motion from the live pulley onto an .adjacent dead pulley for stopping the operation of the spindle. Among the objects of the invention are the following:

To provide a tension device or tensional arrangement which will operate efficiently under conditions where the band is laterally movable as outlined above, and, also, to provide a tension device or tensional arrangement which will possess the following advantages:

One having relatively few parts;

One to which the band may be quickly applied after placing the band .around the driving part and part driven by it;

One which will not require any increase in the normal length of the band;

One that will operate freely and not cause undue wear upon the band adapting itself automatically to the different running positions of the band;

One that may be arranged to increase the extent of frictional engagement betweenthe band and driving cylinder or pulley as the belt stretches; vand Under conditions where the tension device is being used in a twister as referred to above, one that will tend to maintain the band in the plane of the whorl on the spindle as the band stretches, and not to unduly increase the angular position of the band on the whorl which would cause wear.

The invention can best be seen and understood by reference to the drawing in which the tension device is shown as applied tothe tensioning of bands in a twister to which machine the device is especially applicable.

In the drawing:

Fig. 1 is a side elevation of the twister with the tension device applied thereto, only those parts of the twister being shown as are necessary for a proper understanding of the invention.

Fig. 2 is a plan of the live driving pulley and adjacent dead pulleys with applied bands, all as hereinafter referred to.

Fig. 3 is a front elevation of the tension device; and

Fig. 4 is a section on the line 4-4 of Fig. 3.

Referring to the drawing: I represents the driving pulley turning in the direction of the arrow 5 thereon. 2, 2 represent the spindles, each having on it .a whorl 3. The spindles are turned by bands 4 passed around the driving pulley and around the whorls on the respective spindles, the bands running in the directions of the arrows alongside the 10 bands.

lArranged adjacent the driving pulley are dead pulleys 5, and during the operation of the machine each band is movable laterally off the live pulley on to the adjacent dead pulley. Such latl5 eral displacement of the band is incidental to the operation of a stop motion, not shown, which operates through a guide fork E embracing the taut section of the band near the driving pulley to laterally displace the band away from the live 20 puhey in the direction ofthe dead pulley. lThis operation is facilitated by a cam or flange l on the live pulley which, when the band is displaced by the fork, engages the displaced band as the live pulley is rotated and strips the band from the 25 live pulley and transfers itto the dead pulley, the return of the band from the dead pulley on to the live pulley being simply a reversal of this operation.

Arranged adjacent each of the bands is a ten- 30 sion device Iii borne by a bracket arm I I suitably fixed to the frame of the machine. The tension device lo comprises a tension pulley I2 having a grooved rim I3, preferably substantially V-shaped in cross section, over which the band passes. The 35 tension pulley is fast on a shaft I4 which turns in bearings l5 borne by the forked ends of arms i6, IE of a yoke having a cross bar Il connecting said arms and which lies parallel with the shaft of the tension pulley. The bearings I5 are held 40 against outward displacement and the ends of the openings through the bearing closed, by ears I8 fixed tothe arms of the yoke and overlapping the ends of the respective bearings. The bearings I ti are preferably rather widely separated from one 45 another and elongated in order that the shaft I4 bearing the tension pulley may not only rotate thereon but have longitudinal movement therein, thus affording an appreciable lateral play to the tension pulley during its rotation. Secured to 50 the cross bar I'I of the yoke with outward extension at right angles thereto and to the shaft of the friction pulley is a spindle 2li which extends through .and turns within a boss 2I laterally offset from the end of a plate 22. This plate has a lon- 55 a grooved tension gitudinal slot 23 in it and the plate is adjustably secured to the bracket arm l I to extend outwardly therefrom by means of a bolt 24 passed through the slot in the plate and through an opening in the arm and secured by a tightening nut 25 for any adjusted position of the plate. The end of the spindle projecting through .and beyond the boss is provided with a head 26 which has drawing engagement with the end of the boss. Coiled upon the spindle and tensioned between the yoke and the boss a spring 2, one end of which bears against the cross arm I 'l of the yoke and the other against the boss, a washer 28 being preferably interposed between the end of the spring and the boss.

In a tension device thus provided the tension pulley will exert tensional force for taking up slack in the band passed over itdepending 'uponrthe amount of compression of the spring 21, and

depending, also, upon the outward extension .of the plate 22 from the bracket arm Il, in the direction of theV band, this depending upon the adjusted position of the plate on the arm.

The'tension device israrranged to bring `the tension pulley against the slack section of the band as near the driving pulley as possible. The band is applied to the tension pulley simply by retracting the pulley for compressing the spring and thenv releasing the pulley to bear with tensional forceagainst the band for taking up slack in it, the 'band then passing over the tension pulley as though it were an idler.

'When the tension device is initially applied to the band and rthe. band is new the plate 22 will be ixed tohave its :minimum extension from the bracket armv to which it is secured and the spring will be 'compressed inv a'maximum amount. The band is then applied tothe pulley simply by slipping it into the 'grooved rim of the pulley'and the pulley released. vThereupon the turning pul- -ley will tend to form .a slight `bend in the band.

As the band stretches all slack will be taken up as long as the tension pulley'remains in a position to bear tensionally against it. When the stretch 'of the band has become considerable `then an adjustment of the plate 22 with relation to the bracket arm will be required for extending the arm and accordingly bringing the pulley nearer the band. The' bend in the band occasioned by the engagement of the tension pulley is. such as will effect an increased area of frictional contact between the band and the driving pulley preventingslippage and, also, Will bring the 'band into the .plane of the Whorl,.so reducing the angular relation of the band to the whorl preventing wear. In. time the band Will become stretched in such amount that its tensional Ysection lying between the driving pulley and vthe whorl on the spindle will lie substantiallywithinY the plane of the Whorl in which position the band operates with great eiiiciency and with minimum wear upon it.

When the band is moved laterally from the live pulley onto the adjacent auxiliary or dead pulley the tension pulley will then tend to align itself -withV the 'band so that the band will run properly 'through the groove of the pulley and not tend to engage the opposite sides of the groove which would .cause excessive wear. In this connection it would be explained that where pulley is employed to take up slack in a :band it is necessary that the pulley lie in true alignment with the band as it passes tangentiallyonto and 01T the pulley within the groove `in it. If the ,tension pulleyis not in alignment then the band, not lying true within the groove in the pulley, Will extend more or less crosswise of the groove and bear against opposite sides of the groove causing a scraping action as the pulley is rotated on the sides of the 5 band and the band will soon wear out, considering the speed at which the tension pulley is rotated. It may be thought that if the tension pulley were pivotally mounted so as to turn, it would turn automatically as the band was turned, 10 or laterally shifted, and so continue its alignment With the band. It will not do'this however in, any ordinary combinations of driving and lvdriven pulleys and on which driving pulley the bandisfshifted laterally for the reason that when 15 the band is shifted, although the pulley is piv- -'-otal-ly-mounted, it will not turn but remain in its set yposition `(due-.at least in part to the high `rotational speed of the tension pulley tending to holdfitinthe plane of its rotation), the shifted 20 band thenextending. through-thegroove in the l pulleyat ananglesoas .to engage .the-opposite sides `of .the groove fcausingthe. scraping. .action and wear. on .the lband as. before explained. iIn the present arrang,ement..however the pulley-will 25 turnautomatically-with theiband or shiftrisvposition as the position. of. .the band .is rshifted, and this for the following reason.

.As the band .is laterally. displaced bythe guide forkv 6 it will be broughtinto .the pathof .the cam 30fv or ilange Ton the'live pulley-which -engages the band. as the liveupulleyV isxrotated and .throws it onto the auxiliaryor. .dead-pulley with a very quick action. 'When the cam strikes the :fband it makes a bend .oriiexureinit as may ybe seen 35" by reference to Fig. 2. This bend or flexurlestends to shorten the band-With relation tothe tension device thereby increasing zthe tensional bea-ring of the tension pulley against lthe band A,and at the same time. willv .cause a y.slight'longitudinal 40 movement of 4thespindle.2O-bearing'the tension. pulley Within the bearing.2| ,in which itis pivoted. These effects, together with fthe quickblow struck the band v.bythe cam-willsovercome the inertia of the tension pulley and will .cause .fit to turn 45@ into alignment with that portion .of I.theband coming .onto it. This will .cause .fthe band to render properly through the groove inthe pulley a-lthough Ywith va -tendencyto` bear .against one iside of the groove rather than at `the -bottom Vof the 5.0 groove, but .it willV obviate-fany tendency of :the band to engage opposite sides of the groove which is .the thingto be-avoided. While -itisnot-absolutely necessary to provide for a lateral slip `or movement of. the tension pulley yet itiswbetter .to 55'; do this so that the pulley will line up not yonly with that portion .ofthe band Acoming ontto'it, but in .sopfar as possible ,be in. :the lineof ethat portion of the Yband Y.passing on the pulley,. the band then renderingproperlyin the .bottom ofthe 60y groove and notagainst onefside. This lateral slip of the pulley -is-prov-ided for asnpreviously explained. When-the band is returned from the auxiliary. or dead -pulley onto the live pulley, ther operation is substantiallya Vreversal of that ex-n 65 plained, the tension pulley then returning to its initial position.

Having thus fully described"myfinvention I claim anddesire :to secure 'byflietters Patent of the United `States: 7 0

l I'he combination comprising f a rotary driving pulley, -a .driveen-member,` adriving band connecting .said driving. pulley and drivenfmemb'er, an auxiliary gpulley arranged alongsidesaid dri-ving pulley, a tension pulley havingatgrowededgen for receiving said driving band and which pulley is arranged to bear against said band for taking up slack therein, means for flexibly mounting said tension pulley whereby it Will yieldingly bear with tension against said band and whereby it will, also, turn so that it may be brought into alignment with said band as the position of the band becomes changed laterally with relation to the driving pulley, and means for moving the band laterally from one to the other of said driving and auxiliary pulleys and, at the same time, actuate said band to bring the tension pulley into alignment therewith as the position of the band becomes laterally changed, including a member on said driving pulley adapted and arranged to strike and flex said band when the band is moved into the path of said member. y

2. The combination comprising a. rotary driving pulley, a driven member, a driving band connecting said driving pulley and driven member, an auxiliary pulley arranged alongside said driving pulley, a tension pulley having a grooved edge for receiving said driving band and Which pulley is arranged to bear against said band for taking up slack therein, means for exibly mounting said tension pulley whereby it will yieldingly bear with tension against said band and whereby it will, also, turn p-ivotally and With permitted lateral slip so that it may be brought into alignment with said band as the position of the band becomes changed laterally with relation to the driving pulley, and means for moving the band laterally from one to the other of said driving and auxiliary pulleys and, at the same time, actuate said band to bring the tension pulley into alignment therewith as the position of the band becomes laterally changed, including a member on said driving pulley adapted and arranged to strike and ex said band when the band is moved into the path of said member. 

